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Bug: negative and minus sign lexical conflict

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#32 4 comments 1 reaction 0 assignees View on GitHub

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Assessment

Difficulty
3/5
Estimated time
1-2 days
Newbie friendliness
45/100
Issue type
Bug
Clarity
Mostly clear
Activity status
Stale
Tech stack
typescript
Domain
compilers

Research direction

Start at the tokenizer path exercised by evaluate("2 -3") and compare it with the spaced example in the report. Done means the unspaced expression produces the expected result without regressing the spaced form.

Written by the indexing model from the issue text.

Description

When you write code like the following

const expr = "2 -3";
console.log(evaluate(expr)); // 2

You will get 2 instead of -1, this is because the tokenizer parses -3 into a number instead of an operator and a number.

If you want to get -1,please add a space before 3, like below

const expr = "2 - 3";
console.log(evaluate(expr)); // -1
Dominant language
TypeScript
Stars
26
Forks
1
PR merge metrics
No merged PRs in 30d

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First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

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